100l (document buffer padding requirements)

Originally committed as revision 1866 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/common.c

@@ -123,6 +123,12 @@ void put_string(PutBitContext * pbc, char *s)
 
 #endif //CONFIG_ENCODERS
 
+/**
+ * init GetBitContext.
+ * @param buffer bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE bytes larger then the actual read bits
+ * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
+ * @param bit_size the size of the buffer in bits
+ */
 void init_get_bits(GetBitContext *s,
                    const uint8_t *buffer, int bit_size)
 {

libavcodec/utils.c

@@ -343,9 +343,15 @@ int avcodec_encode_video(AVCodecContext *avctx, uint8_t *buf, int buf_size,
     return ret;
 }
 
-/* decode a frame. return -1 if error, otherwise return the number of
+/** 
-   bytes used. If no frame could be decompressed, *got_picture_ptr is
+ * decode a frame. 
-   zero. Otherwise, it is non zero */
+ * @param buf bitstream buffer, must be FF_INPUT_BUFFER_PADDING_SIZE larger then the actual read bytes
+ * because some optimized bitstream readers read 32 or 64 bit at once and could read over the end
+ * @param buf_size the size of the buffer in bytes
+ * @param got_picture_ptr zero if no frame could be decompressed, Otherwise, it is non zero
+ * @return -1 if error, otherwise return the number of
+ * bytes used. 
+ */
 int avcodec_decode_video(AVCodecContext *avctx, AVFrame *picture, 
                          int *got_picture_ptr,
                          uint8_t *buf, int buf_size)